class_docstr: Appends a constant value to each node feature :obj:`x`
  (functional name: :obj:`constant`).
  
  Args:
      value (float, optional): The value to add. (default: :obj:`1.0`)
      cat (bool, optional): If set to :obj:`False`, existing node features
          will be replaced. (default: :obj:`True`)
      node_types (str or List[str], optional): The specified node type(s) to
          append constant values for if used on heterogeneous graphs.
          If set to :obj:`None`, constants will be added to each node feature
          :obj:`x` for all existing node types. (default: :obj:`None`)
code: def __repr__(self) -> str:
      return f"{self.__class__.__name__}(value={self.value})"
  
file_path: pytorch_geometric/torch_geometric/transforms/constant.py
imports: from typing import List, Optional, Union
  import torch
  from torch_geometric.data import Data, HeteroData
  from torch_geometric.data.datapipes import functional_transform
  from torch_geometric.transforms import BaseTransform
label_desc: Use image node_id 3 for calling the Constant obj's underlying member method code with example usage: obj.__repr__() and returns: self, str, self, str